Urodynamic effects of dutasteride add-on therapy to alpha-adrenergic antagonist for patients with benign prostatic enlargement: prospective pressure-flow study.

AIMS: We prospectively investigated the effect of dutasteride on clinical and urodynamic parameters in patients with benign prostatic enlargement (BPE).

MATERIALS AND METHODS: A prospective study was conducted in consecutive 52 patients with BPE who had not been satisfied with alpha-adrenergic antagonist monotherapy. Inclusion criteria were prostate volume (PV) ≥30 ml and the International Prostate Symptom Score (IPSS) ≥8 or QOL index ≥3 under administration of an alpha-adrenergic antagonist without anticholinergic agent. Before and 24 weeks after dutasteride (0.5 mg daily) add-on treatment with preceding alpha-adrenergic antagonist, we assessed IPSS, uroflowmetry (UFM), filling cystometry, and pressure-flow study (PFS).

RESULTS: Dutasteride add-on treatment significantly improved IPSS (from 18.4 ± 7.5 to 13.8 ± 7.3) and maximum flow rate (from 11.4 ± 5.6 to 13.0 ± 6.8 ml/sec). Maximum cystometric capacity on filling cystometry did not change significantly by dutasteride add-on treatment (221 ± 97 and 240 ± 104 ml before and after dutasteride add-on, respectively). All of the 41 patients with detrusor overactivity (DO) before dutasteride add-on treatment showed apparent reduction in the amplitude of involuntary detrusor contraction after dutasteride add-on treatment, including seven in whom DO disappeared. Dutasteride significantly reduced PV from 66.4 ± 31.9 to 47.6 ± 26.1 ml. In PFS, detrusor pressure at maximum flow rate (PdetQmax) significantly decreased from 71.5 ± 30.1 to 59.1 ± 24.9 cmH2O after dutasteride add-on treatment. Bladder outlet obstruction index (BOOI) also decreased significantly from 55.2 ± 31.9 to 42.3 ± 27.9, and obstruction grade assessed by the Schäfer nomogram significantly improved.

CONCLUSIONS: Dutasteride can improve lower urinary tract symptoms by improving storage bladder function and relieving obstruction.